Hello,
Thanks for reaching out here in the Microsoft Answers Community.
Based on the description, it seems that the touchpad itself is not functioning properly.
Try updating the drivers first. To do so, right-click Start->Settings->Windows update, and install all available updates, including the optional ones in advanced options. See whether the touchpad works.
If the touchpad still does not work, please connect the external USB mouse, right-click Start->Device manager, expand the "Human interface devices", "Mice and other pointing devices", and "Other devices" section, and provide a screenshot.
We look forward to your response.
Best Regards,
Sheng G. - MSFT | Microsoft Community Support Specialist